Is There Any Essential Control in Informal Requirements?

The overriding aim must be to avoid state and control where they are not absolutely and truly essential. If you don't need it, get rid of it. Unavoidable accidental complexity must be separated out from the rest of the system. We should restrict ourselves to simply declaring what accidental state should be used - leave it to a completely separate infrastructure to maintain. And then ease of expression, sometimes things are easiest to express with state. I mean, that's just often the case.